Precoded massive MU-MIMO uplink transmission under transceiver I/Q imbalance
Precoded massive MU-MIMO uplink transmission under transceiver I/Q imbalance
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DOI：
10.1109/glocomw.2014.7063451
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发表时间：
2014-12
期刊：
影响因子：
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通讯作者：
Aki Hakkarainen;J. Werner;K. Dandekar;M. Valkama
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文献类型：
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作者：
Aki Hakkarainen;J. Werner;K. Dandekar;M. Valkama
在大规模多输入多输出(MIMO)系统中，结合数字阵列处理，相关的射频(RF)前端的数量不可避免地很高。本文研究了在预编码大规模多用户MIMO(MU-MIMO)上行链路传输中，这些射频前端的缺陷对系统整体性能的影响。特别是，我们关注收发机的同相/正交(I/Q)不平衡及其利用射频感知空间处理的缓解。本文首先推导了I/Q不平衡下基于OFDMA的大规模MU-MIMO上行链路系统的基本失真和干扰模型，然后提出在上行链路接收器(RX)中进行增广的空间后处理，以有效地抑制有害影响。数值例子表明，增广空间RX处理的性能明显优于传统的线性处理，从而以实用的低成本射频前端提供了显著的性能改善。
In massive multiple-input multiple-output (MIMO) systems, combined with digital array processing, the amount of the associated radio frequency (RF) front-ends is inevitably high. This paper addresses how imperfections in these RF front-ends affect the overall system performance in precoded massive multiuser MIMO (MU-MIMO) uplink transmission. In particular, we focus on transceiver in-phase/quadrature (I/Q) imbalances and their mitigation with RF-aware spatial processing. We first derive the essential distortion and interference models for OFDMA-based massive MU-MIMO uplink system under I/Q imbalances, and then propose augmented spatial post-processing to be carried out in the uplink receiver (RX) for mitigating the harmful effects efficiently. Numerical examples show that the augmented spatial RX processing clearly outperforms the conventional linear processing, and thus provides significant performance improvements with practical low-cost RF front-ends.